In any hybrid power vehicle or electric vehicle, a battery heavy in weight and large in size has to be provided, which causes severely increased weight of the vehicle. The existing fuel-fired vehicle body can't meet the requirement of hybrid power vehicle or electric vehicle in structure and intensity, therefore, corresponding components of the vehicle body must be improved further. The existing floorboard assembly for vehicle usually comprises a front floorboard, a middle floorboard, a rear floorboard, and a variety of mounting brackets fixed to the floorboard. Usually, the part from the front wall panel to the rear seat board is referred to the front floorboard, the part from the rear seat board to the luggage compartment is referred to the middle floorboard, and the part behind the luggage compartment is referred to the rear floorboard. The front floorboard is roughly in flat shape and is slightly raised in the middle for arranging a shift control, a hand brake and auxiliary instrument panel, and is welded with the front wall panel for vehicle together; a mounting bracket for the shift control assembly, a mounting bracket for the auxiliary instrument panel, and rear mounting brackets for the seats, etc. are fixed. The existing low-capacity and small-size battery usually can be arranged in the vehicle, i.e., below or behind the rear seats. However, since the battery capacity is low, such a hybrid power vehicle has short travel mileage. In order to increase the travel mileage of the hybrid power or electric vehicles, a high-capacity battery must be provided, which will cause increased weight and volume of the battery pack inevitably; if the battery is arranged in the vehicle, it will occupy a large space in the vehicle, and the installation and maintenance of the battery will be inconvenient, and the gravity center of the vehicle will not be stable.